Cell specialisation and organisation Flashcards
Why do we have specialised cells?
No one cell can provide the best conditions for each basic function.
What is a specialised cell?
Cells adapted to perform a certain function. Each specialised cell has evolved fewer or more of certain organelles and structures to suit the role it carries out.
As an embryo all the cells are…
Identical.
As an embryo matures what happens?
Each cell takes on individual characteristics that suit it to the function it will perform when it’s mature.
How are all cells in a human created?
Mitotic division of a fertilised egg.
How does a cell become specialised?
Only some genes are switched on (expressed) in any one cell, at any one time. Different genes are switched on in each type of specialised cell. The rest are switched off.
What is the result of many specialised cells?
The whole organism functions efficiently.
What is a tissue?
A collection of similar cells that perform a specific function.
Epithelial tissue-function and what is it made of?
Made of sheets of cells, they line the surfaces of organs and often have a protective or secretory function.
Xylem-function?
It transports water and mineral ions around the plant, it also gives some mechanical support.
What is an organ?
A combination of tissues that are coordinated to perform a variety of functions, although usually have one predominant function.
Stomach is an example of an organ, how do the tissues work?
Muscle churns and mixes the food, epithelium protects the stomach wall and produces secretions, connective tissue holds together the other tissues.
What is an organ system?
Organs that work together as a single unit. They are grouped together to perform particular functions efficiently.
Digestive system is an organ system- what is included and what is the function?
It digests and processes food. Includes: salivary glands, oesophagus, stomach duodenum, ileum, pancreas and liver.
Why are capillaries not organs?
They are only made up of one tissue. (Epithelium)
